Colossal piezoresistance in narrow-gap Eu5In2Sb6

TL;DR

This paper reports the discovery of colossal piezoresistance in Eu$_5$In$_2$Sb$_6$ crystals, driven by anisotropic metallic clusters within a semiconducting matrix, leading to potential multi-functional device applications.

Contribution

It introduces a new material exhibiting unprecedented piezoresistance due to electronic interactions and phase separation, expanding the understanding of piezoresistive effects.

Findings

Resistivity drops over 99.95% under 0.4 GPa pressure

Piezoresistance factor of $5000\times10^{-11}$ Pa$^{-1}$

Anisotropic metallic clusters cause colossal piezoresistance

Abstract

Piezoresistance, the change of a material's electrical resistance ($R$) in response to an applied mechanical stress ($\sigma$), is the driving principle of electromechanical devices such as strain gauges, accelerometers, and cantilever force sensors. Enhanced piezoresistance has been traditionally observed in two classes of uncorrelated materials: nonmagnetic semiconductors and composite structures. We report the discovery of a remarkably large piezoresistance in Eu$_5$In$_2$Sb$_6$ single crystals, wherein anisotropic metallic clusters naturally form within a semiconducting matrix due to electronic interactions. Eu$_5$In$_2$Sb$_6$ shows a highly anisotropic piezoresistance, and uniaxial pressure along [001] of only 0.4~GPa leads to a resistivity drop of more than 99.95\% that results in a colossal piezoresistance factor of $5000\times10^{-11}$Pa$^{-1}$. Our result not only reveals the role of interactions and phase separation in the realization of colossal piezoresistance, but it also highlights a novel route to multi-functional devices with large responses to both pressure and magnetic field.